Improved crystal quality of AlGaN by Al ion-implantation sapphire substrate

AlGaN as a key material offers a route to high-efficiency optical and electronic devices. However, the heteroepitaxy of AlGaN confronts many challenges, and the crystal quality of AlGaN is still poor. Here, we show an effective method to improve the AlGaN crystal quality through the pretreatment of Al-ion implantation into the sapphire substrate. Our results demonstrate the screw and edge dislocation density of the AlGaN grown on the Alion implantation sapphire substrate are both reduced. At an Al-ion dose of 1 x 1012 cm-2, the screw and edge dislocation density are significantly reduced from 8.9 x 107 to 8.2 x 106, and 4.6 x 1010 to 3.3 x 1010 cm-2, respectively. The photoluminescence spectra also indicate enhanced optical performance. This innovative method is effective and simple for reducing the dislocation density of AlGaN epilayers and can be extended to other substrates for AlGaN epitaxy.

Automated summary

Improving the crystal quality of AlGaN can be achieved by pretreating the sapphire substrate with Al-ion implantation. The results show that the screw and edge dislocation densities of AlGaN grown on the Al-ion implanted sapphire substrate are reduced. At an Al-ion dose of 1 x 1012 cm-2, the screw and edge dislocation densities are significantly reduced. The photoluminescence spectra also indicate enhanced optical performance. This innovative method can effectively reduce the dislocation density of AlGaN epilayers and can be applied to other substrates for AlGaN epitaxy.